Vaporizing pot type oil burner



Sept 8, 1964 R. H. MUELLER 3,147,796 VAPORIZING POT TYPE on. BURNER Filed Feb. 21, 1962 OOOOOOOOOOOOOOO 00000000 lNVEN TOR.

' United States Patent 3,147,796 VAPORIZING POT TYPE OIL BURNER Richard H. Mueller, Milwaukee, Wis, assignor to Controls Company of America, Schiller Park, 11]., a corporation of Delaware Filed Feb. 21, 1962, Ser. No. 174,799 3 Claims. (Cl. 158-91) The invention relates to an improvement in vaporizing pot type oil burners. One purpose is to provide improved pilot means for such a burner.

Another purpose is to provide an improved segmental pilot structure for such a burner.

Another purpose is to provide a segmental pilot structure which produces a clean flame with a minimum of smoke and soot.

Another purpose is to provide such a pilot structure which maintains a stable flame, free from the self-extinguishing characteristics of prior art segmental burners.

Another purpose is to provide a flame pattern which will spread more or less evenly over the area of the burner bottom, whereby to prevent metal fatigue and bottom failure.

Other purposes will appear from time to time in the course of the specification and claims.

I illustrate the invention more or less diagrammatically in the accompanying drawings wherein:

FIGURE 1 is a vertical axial section of a pot and pilot structure;

FIGURE 2 is a plan View of the pilot structure;

FIGURE 3 is a side elevation of the structure of FIG- URE 2; and

FIGURE 4 is an end elevation of the structure of FIG- URE 2.

Like parts are indicated by like symbols throughout the specification and drawings.

Referring to the drawings, A generally indicates a burner pot which has a circumferential, generally cylindrical pot side wall 1. The pot bottom 2 is upwardly concave, being slightly dished toward the center or vertical axis of the pot. The side wall is provided with a plurality of primary air inlets 3, circumferentially spaced about the side wall and located at various distances from the open end or top of the pot. 4 indicates a free upper edge of the burner pot adjacent to which is secured an upper annulus or ring 5 which, in effect, forms an upward continuation of the pot. This upper ring 5 is perforated by a series of secondary air inlets 6, shown as slightly upwardly tilted. Additional inlets 7 are positioned to direct air inwardly toward the pot side wall at a level below the upper edge 4 of such wall. This provides an upwardly flowing body of air moving toward the bases of the air jets delivered by the apertures or inlets 6. 8 indicates an outwardly extending flange which seats on any suitable support 9 which, in turn, may be secured to or form part of any suitable stove or heater element, not herein shown. 10 indicates an outer housing which defines a plenum chamber 11 and which has a bottom 12 having an air inlet aperture 13. In the form herein shown all of the air admitted for passage into the pot through the above mentioned apertures enters the plenum chamber 11 through the aperture 13 and against the exterior of the pot bottom 2.

I provide a pilot housing of the so-called quadrant or segmental type, which is shown in detail in FIGURES 2, 3 and 4. I prefer to employ cast iron as the material but it will be understood that I do not limit myself to such material. The pilot structure includes generally radial side walls 20 which converge and which, if their plane were continued until they meet, would surround a space extending to or slightly beyond the vertical axis of the pot. This axis is indicated, for example, at X in FIG- URES 2 and 3. A downwardly and inwardly sloping top wall 21 completes the pilot housing, the outer end of which is preferably open to the side wall of the pot. It may be secured to the pot in any suitable way. I illustrate, for example, securing ears 22 which may receive or be engaged by supporting screws or the like 23. A row of relatively large and closely spaced pilot air holes 24 is formed in the side wall to communicate with the upper part of the interior of the pilot housing. It will be understood, of course, that such punching may be widely varied, but I illustrate a group of holes which are practical and efficient as to size and location. The pilot housing terminates in an inner opening or neck, indicated at 29a, which communicates with a space 25 surrounded by a wall or baffle 26. This wall is shown as generally U-shaped, the arms of the U being secured to or continuous with the side walls 20 of the pilot housing. The wall 26 terminates somewhat above the bottom of the pot, and surrounds an upwardly open space. If desired, spacing or supporting lugs 27 may be employed, which leave open spaces 28. Thus the space 25 is in communication, both above and below, with the interior of the pot. The slope of the top wall is selected to direct the primary air admitted through apertures 24 toward the open spaces 28 thereby spreading the rich fuel-air mixture radially outward from the baffle 26 and across the pot bottom. The flow of air and vaporized fuel through space 25 will create a slight down draft at the inner surface of the bafile drawing some of the rich fuel-air mixture from the interior of the pot down into space 25 where it will mix with the rich fuel-air mixture coming out of the pilot housing. Air apertures 29 are formed in the short horizontal extension 36) of the top wall 21 of the pilot housing. These provide a secondary air supply for the mixture of primary air and vaporized fuel flowing through the pilot housing.

A pilot ring 35 may be employed intermediate top and bottom of the pot. It may be mounted on any suitable support or studs 36, and in the structure herein shown is indicated as positioned above the lowest row of primary air inlets 3.

Liquid fuel is delivered to the interior of the pilot housing through any suitable oil inlet 40. It will be understood that the liquid fuel flows downwardly and inwardly over the pot bottom into a space which is snugly surrounded by the side walls 20 and the top wall 21.

In considering the operation of the device, at the pilot stage a relatively small flow of a suitable liquid fuel is supplied through the inlet 40, and flows inwardly toward the center of the pot. It receives primary air through air inlets 24 and is vaporized by the heat of the combustion taking place at or adjacent the space 25. The result of the inflow of primary air through the apertures 24 is to produce a relatively rich mixture of air and vaporized fuel. This rich mixture receives some secondary air through the inlets 29, and the final mixture, at the pilot stage, is thus rendered combustible. The slope of the top wall will direct the primary air and vaporized fuel toward spaces 28 causing the flame to fan out beneath the wall and across the pot bottom. The U-shaped Wall slows up the flow of the premixed gases in the vicinity of the outlet of the pilot housing for a period of time effective to permit a proper air-vapor mixture conducive to a stable, continuously burning pilot flame. The wall 26, likewise, is elfective to reduce the velocity of the flame leaving the mouth or opening of the pilot structure. This reduction of velocity is effective to prevent flame extinguishment which, in prior art structures, has arisen when the velocity of the flame jet exceeds the rate of flame propagation. This pulling or self-extinguishment is prevented by the herein described structure.

i of the invention.

The slope of the top wall of the structure is effective in causing the pilot flame to spread out through spaces 28 more or less evenly over the area of the burner bottom about the wall 26. This prevents the smoky candling effect created in the center of the pot and equalizes bottom temperatures preventing metal fatigue and failure of the pot bottom. The pilot flame is not directly dependent upon air entering the burner side walls, except the primary supply admitted through the apertures 24. The secondary air admitted at the mouth of the pilot housing and through the inlets 29 insures flame propagation at this point and provides the fuel-air ratio necessary to support clean combustion.

It will be realized that, whereas, I have described and illustrated a practical and operative device, nevertheless many changes may be made in the size, shape, number and disposition of parts without departing from the spirit I therefore wish my description and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as limiting me to my precise showing.

The use and operation of the invention are as follows: I illustrate herein a typical vaporizing pot type oil burner in which, at the full combustion stage, air is admitted through apertures located at various levels in the pot side wall. The lower of these apertures admit so-called primary air into the pot, for mixture with the fuel vaporized by combustion taking place at a higher level. This rich mixture rises in the pot and does not burn until it receives an additional air supply, the socalled secondary air. In the structure of the present application the secondary air is delivered by the topmost row of holes about the pot, and, at high fire, combustion takes place at or above the top of the pot, the flame normally extending up into whatever heater or stove or heat-transfer element is used. The rate of combustion is regulated by varying or controlling the flow of liquid fuel into the pot. As the rate of flow of the liquid fuel is reduced, the level of combustionwithin the pot, the zone where full combustion takes place, drops closer and closer to the pot bottom. At the lowest stage or rate, only enough fuel is admitted through the inlet 40 to maintain a localized pilot combustion at the inner end of the pilot housing. This combustion takes place at or near the space 25. Some flame may rise upwardly but, under normal conditions, the flame will spread out across the pot bottom due to the slope of the top of the pilot housing directing the flow of primary air toward spaces 28. In the use of the structure as described and shown herein the U-shaped wall or baffle 26, taken in connection with the secondary air supply through the holes 29, is effective in maintaining a stable or continuously burning flame which is clean and which does not snuff out. The spread or pattern of the pilot flame, the flame being generally evenly distributed over an area of the burner bottom, equalizes bottom temperatures. This eliminates metal fatigue or heat failure of the pot bottom. The distribution of the flame over the pot bottom insures complete combustion during the initial operation of the burner thereby preventing the smoky column commonly noted in the center of the burner.

I claim:

1. In a pilot burner housing construction, a housing member provided with an opening at an outer end thereof adapted to abut the inner surface of a burner pot sidewall to receive a supply of primary air and fuel through said pot sidewall, said housing including sidewall members converging towards a restricted opening provided in the opposite inner end of the housing for the discharge of an air fuel mixture from the housing, an extension member carried by the housing and projecting beyond and overhanging the restricted opening in the inner end of the housing, a generally upright upwardly open baffle structure disposed in inwardly spaced relation to said restricted opening and in line with the flow of fuel air mixture to be discharged therefrom, said batfle structure including an upstanding wall member. laterally confining the fuel air mixture discharged through said restricted opening and means provided within said extension member for feeding secondary air downwardly beneath said extension member and into the fuel-air mixture discharged into the space within said confining wall member from said housing.

2. The uprights described in claim 1 wherein the converging sidewalls of the housing member are extended and joined together to provide the baffle structure and the upstanding confining wall.

3. The apparatus described in claim 1 wherein the space within the upstanding confining wall of the baffle structure and above said extension member of the housing is unrestricted upwardly.

ReferencesCited in the file of this patent UNITED STATES PATENTS 2,460,013 Huston Jan. 25, 1949 2,537,735 Cargile et al Jan. 9, 1951 2,579,293 Breese Dec. 18, 1951 2,579,370 Donley Dec. 18, 1951 2,579,372 Donley Dec. 18, 1951 2,748,847 Gilmore et al June 5, 1956 

1. IN A PILOT BURNER HOUSING CONSTRUCTION, A HOUSING MEMBER PROVIDED WITH AN OPENING AT AN OUTER END THEREOF ADAPTED TO ABUT THE INNER SURFACE OF A BURNER POT SIDEWALL TO RECEIVE A SUPPLY OF PRIMARY AIR AND FUEL THROUGH SAID POT SIDEWALL, SAID HOUSING INCLUDING SIDEWALL MEMBERS CONVERGING TOWARDS A RESTRICTED OPENING PROVIDED IN THE OPPOSITE INNER END OF THE HOUSING FOR THE DISCHARGE OF AN AIR FUEL MIXTURE FROM THE HOUSING, AN EXTENSION MEMBER CARRIED BY THE HOUSING AND PROJECTING BEYOND AND OVERHANGING THE RESTRICTED OPENING IN THE INNER END OF THE HOUSING, A GENERALLY UPRIGHT UPWARDLY OPEN BAFFLE STRUCTURE DISPOSED IN INWARDLY SPACED RELATION TO SAID RESTRICTED OPENING AND IN LINE WITH THE FLOW OF FUEL AIR MIXTURE TO BE DISCHARGED THEREFROM, SAID BAFFLE STRUCTURE INCLUDING AN UPSTANDING WALL MEMBER LATERALLY CONFINING THE FUEL AIR MIXTURE DISCHARGED THROUGH SAID RESTRICTED OPENING AND MEANS PROVIDED WITHIN SAID EXTENSION MEMBER FOR FEEDING SECONDARY AIR DOWNWARDLY BENEATH SAID EXTENSION MEMBER AND INTO THE FUEL-AIR MIXTURE DISCHARGED INTO THE SPACE WITHIN SAID CONFINING WALL MEMBER FROM SAID HOUSING. 